Researchers find early development may trigger weight gain

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PORTLAND, Ore. — A gene that delays female puberty and may be linked to obesity has been identified by Oregon Health & Science University researchers. Experiments with mice suggest that absence of the gene in the area of the brain called the hypothalamus delays the onset of puberty.

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Sergio Ojeda, a senior scientist at the OHSU Oregon National Primate Research Center who led the study, said a number of research papers have indicated recently that girls are reaching puberty at an earlier age.

"While there is no definitive information ... other research has suggested that if this is the case, it may be linked to the nation's obesity crisis," Ojeda said.

The gene, called TTF-1, is expressed in the hypothalamus during sexual development.

The mouse study suggested the gene not only affects the timing of puberty, it can shorten the time span during the life of the animal for reproduction.

The researchers found that mice lacking the TTF-1 gene had fewer litters, had fewer pups in each litter, and their reproductive time span was half that of a normal animal.

Prior to the mouse study, Ojeda's research team found similar results with rats, followed by studies confirming that expression of the TTF-1 gene increases in the hypothalamus of nonhuman primates at the onset of puberty.

Ojeda and his colleagues now are tracking other genes that might interact with TTF-1 in the brain to control the onset of puberty in animals and humans.

"We know that children recently described to have mutations of this gene suffer from loss of motor coordination and alterations in fluid balance," said Ojeda.

The study was presented Sunday at the annual Society for Neuroscience meeting in San Diego.